What provision is now made in many cities to handle rain water and other surface waters in such a way that they may not have to enter and overload the public sewage system?

This is accomplished by installing separate sewer systems, known as surface sewers, for the reception of all surface water, none of the latter being carried into the regular system of sewers.

How should trap cleanouts be located to give the best results?

They should be placed so that they are at all times under water.

The advantage of such submerged cleanouts is that there is no opportunity for the passage through defective gaskets, of sewer gases and odors, any defect being at once made apparent by the leakage through the cleanout cover. Generally traps provided with such cleanouts may be more easily cleaned.

Why is the use of exposed metal surfaces to be avoided in the construction of urinals?

For the reason that the acids of the waste entering the urinal attack metals and corrode them, thereby making the fixture more filthy than it need be.

Describe the operation of the pneumatic water supply system.

The operating force of this system is compressed air. An air-tight storage tank is used, which may be placed underground or in the basement or cellar, thus doing away with the objectionable attic tank. As water is pumped into the tank, the air already contained in the tank is compressed, the amount of compression increasing as the tank fills. By means of the pressure produced by this compressed air, water may be delivered by this system under as high pressure as 75 pounds, which is ample not only for house and stable purposes, but also for garden and fire use.

If sufficient pressure cannot be obtained by ordinary means, a special valve may be used on the suction pipe, which will draw in air with each stroke of the pump, in any desired quantity. On large work, such as the supplying of water under pressure to institutions, small towns, etc., several tanks may be used to provide the necessary storage, and if necessary, a special air pump to provide air pressure. This system is of great value in sections that are not provided with a public supply.